Project Summary Establishing early nutrition support post traumatic injury is the standard of care in ICU's. There is ample evidence that early enteral nutrition (within 24-48 hours post injury) is associated with positive outcomes, but controversy persists regarding the optimal amount of nutrition to be fed in the first week post injury. The avoidance of overfeeding to prevent hyperglycemia and fluid overload with a caloric goal of 60-80% of energy requirements may prove optimal as long as there is a supply of protein of at least 1.5 grams/kg /day. Our plan is to randomize in a blinded fashion patients admitted to the Surgical Intensive Care Unit at Boston Medical Center to either receive a peripherally infused amino acid solution to provide at least 1.5 grams pro/kg from within 24 hours of injury or placebo, which is D10W infused at a similar rate for 5 days. These infusions will supplement the normal enteral feedings prescribed and advanced as tolerated for patients in both groups. Measurements will be taken at baseline and again on day 4-5 for plasma markers of inflammation (cytokines) and a metabolomics profile. A 24 hour urine collection will be obtained on day 1 and day 5 in both groups to determine nitrogen balance and Catabolic Index. After five days, infusions will be stopped and patients will continue on their enteral feedings as tolerated. Estimates of daily nutrition intake, incidence of infection and organ dysfunction will be recorded. APACHE II, SIRS and SOFA scores will be measured daily for the first 5 days and then every three days until day 28, discharge or death. The investigators will track the incidence of infections (blood, urine, wound, lung) during their hospitalization using published definitions from Critical Care Medicine. Our primary outcome is to see a difference in the metabolomics profile in the protein infusion group supporting improved protein economy and possibly less fatty acid mobilization. We also anticipate less of an inflammatory response with the amino acid infusion and improved nitrogen balance.